Decision to return to sport participation after anterior cruciate ligament reconstruction, Part II: Self-reported and functional performance outcomes

Context: Anterior cruciate ligament (ACL) reconstruction (ACLR) is the most commonly used method for helping athletes regain function and return to preinjury activity levels after ACL injury. Outcomes after ACLR have suggested that athletes return to a level of function that would support a return to sport participation; however, in a recent meta-analysis, pooled return rates were only 55%. It is unclear whether this discrepancy is a result of functional impairments. Objective: To compare patient-reported outcomes (PROs), dynamic balance, dynamic functional performance, strength, and muscular endurance in athletes who returned to sport (RTS) and athletes who did not return to sport (NRTS) after ACLR. Design: Case-control study. Setting: University research laboratory. Patients or Other Participants: Two groups of participants with primary unilateral ACLR: 18 RTS individuals (7 males, 11 females; age = 23 ± 11 years, height = 163.58 ± 40.41 cm, mass = 70.00 ± 21.75 kg, time since surgery = 4.02 ± 3.20 years) and 12 NRTS individuals (5 males, 7 females; age = 26 ± 13 years, height = 171.33 ± 48.24 cm, mass = 72.00 ± 21.81 kg, time since surgery = 3.68 ± 2.71 years). Intervention(s): The PROs consisted of the International Knee Documentation Committee Subjective Knee Evaluation Form, Knee Injury and Osteoarthritis Outcome Score, Tegner Activity Scale, and Marx Activity Scale. Functional performance outcome measures were the anterior and posteromedial reach on the Star Excursion Balance Test, a battery of single-legged-hop tests, isokinetic quadriceps and hamstrings strength at 608/s and 1808/s, and a novel step-down-to-fatigue test. All measures were taken during a single laboratory session. Main Outcome Measure(s): The Limb Symmetry Index was calculated for all functional performance measures. Mann-Whitney U tests were used to compare measures between groups (P > .10). Results: Compared with the RTS group, the NRTS group had lower scores on the International Knee Documentation Committee Subjective Knee Evaluation Form (RTS median = 92.52, range = 66.67-97.70; NRTS median = 82.76, range = 63.22-96.55; P = .03) and Knee Injury and Osteoarthritis Outcome Score Symptoms subscale (RTS median = 88, range = 54-100; NRTS median = 71, range = 54-100; P = .08). No differences were observed for any functional performance measures. Conclusions: The NRTS athletes displayed lower PROs despite demonstrating similar function on a variety of physical performance measures. These results further support existing evidence that physical performance alone may not be the ideal postoperative outcome measure. Measures of patients' symptoms and self-perceived physical function may also greatly influence postoperative activity choices.